OpenRaiser/Intern-Atlas huggingface dataset:
Qualitative Properties of alpha-Weighted Scheduling Policies
Venue: arXiv cs.NI 2010
Year: 2010

We consider a switched network, a fairly general constrained queueing network model that has been used successfully to model the detailed packet-level dynamics in communication networks, such as input-queued switches and wireless networks. The main operational issue in this model is that of deciding which queues to serve, subject to certain constraints. In this paper, we study qualitative performance properties of the well known $α$-weighted scheduling policies. The stability, in the sense of positive recurrence, of these policies has been well understood. We establish exponential upper bounds on the tail of the steady-state distribution of the backlog. Along the way, we prove finiteness of the expected steady-state backlog when $α<1$, a property that was known only for $α\geq 1$. Finally, we analyze the excursions of the maximum backlog over a finite time horizon for $α\geq 1$. As a consequence, for $α\geq 1$, we establish the full state space collapse property.
Maximal Intersection Queries in Randomized Input Models
Venue: arXiv cs.IR 2010
Year: 2010

Consider a family of sets and a single set, called the query set. How can one quickly find a member of the family which has a maximal intersection with the query set? Time constraints on the query and on a possible preprocessing of the set family make this problem challenging. Such maximal intersection queries arise in a wide range of applications, including web search, recommendation systems, and distributing on-line advertisements. In general, maximal intersection queries are computationally expensive. We investigate two well-motivated distributions over all families of sets and propose an algorithm for each of them. We show that with very high probability an almost optimal solution is found in time which is logarithmic in the size of the family. Moreover, we point out a threshold phenomenon on the probabilities of intersecting sets in each of our two input models which leads to the efficient algorithms mentioned above.
From Playability to a Hierarchical Game Usability Model
Venue: arXiv cs.HC 2010
Year: 2010

This paper presents a brief review of current game usability models. This leads to the conception of a high-level game development-centered usability model that integrates current usability approaches in game industry and game research.
On Memory Accelerated Signal Processing within Software Defined Radios
Venue: arXiv cs.NI 2010
Year: 2010

Since J. Mitola's work in 1992, Software Defined Radios (SDRs) have been quite a hot topic in wireless systems research. Though many notable achievements were reported in the field, the scarcity of computational power on general purpose CPUs has always constrained their wide adoption in production environments. If conveniently applied within an SDR context, classical concepts known in computer science as space/time tradeoffs can be extremely helpful when trying to mitigate this problem. Inspired by and building on those concepts, this paper presents a novel SDR implementation technique which we call Memory Acceleration (MA) that makes extensive use of the memory resources available on a general purpose computing system, in order to accelerate signal computation. MA can provide substantial acceleration factors when applied to conventional SDRs without reducing their peculiar flexibility. As a practical proof of this, an example of MA applied in the real world to the ETSI DVB-T Viterbi decoder is provided. Actually MA is shown able to provide, when applied to such Viterbi decoder, an acceleration factor of 10.4x, with no impact on error correction performances of the decoder and by making no use of any other typical performance enhancement techniques such as low level (Assembler) programming or parallel computation, which though remain compatible with MA. Opportunity for extending the MA approach to the entire radio system, thus implementing what we call a Memory-Based Software Defined Radio (MB-SDR) is finally considered and discussed.
A hybrid decision approach for the association problem in heterogeneous networks
Venue: arXiv cs.GT 2010
Year: 2010

The area of networking games has had a growing impact on wireless networks. This reflects the recognition in the important scaling advantages that the service providers can benefit from by increasing the autonomy of mobiles in decision making. This may however result in inefficiencies that are inherent to equilibria in non-cooperative games. Due to the concern for efficiency, centralized protocols keep being considered and compared to decentralized ones. From the point of view of the network architecture, this implies the co-existence of network-centric and terminal centric radio resource management schemes. Instead of taking part within the debate among the supporters of each solution, we propose in this paper hybrid schemes where the wireless users are assisted in their decisions by the network that broadcasts aggregated load information. We derive the utilities related to the Quality of Service (QoS) perceived by the users and develop a Bayesian framework to obtain the equilibria. Numerical results illustrate the advantages of using our hybrid game framework in an association problem in a network composed of HSDPA and 3G LTE systems.
Improved Sparse Recovery Thresholds with Two-Step Reweighted $\ell_1$ Minimization
Venue: arXiv cs.IT 2010
Year: 2010

It is well known that $\ell_1$ minimization can be used to recover sufficiently sparse unknown signals from compressed linear measurements. In fact, exact thresholds on the sparsity, as a function of the ratio between the system dimensions, so that with high probability almost all sparse signals can be recovered from iid Gaussian measurements, have been computed and are referred to as "weak thresholds" \cite{D}. In this paper, we introduce a reweighted $\ell_1$ recovery algorithm composed of two steps: a standard $\ell_1$ minimization step to identify a set of entries where the signal is likely to reside, and a weighted $\ell_1$ minimization step where entries outside this set are penalized. For signals where the non-sparse component has iid Gaussian entries, we prove a "strict" improvement in the weak recovery threshold. Simulations suggest that the improvement can be quite impressive-over 20% in the example we consider.
Applications of Lindeberg Principle in Communications and Statistical Learning
Venue: arXiv cs.IT 2010
Year: 2010

We use a generalization of the Lindeberg principle developed by Sourav Chatterjee to prove universality properties for various problems in communications, statistical learning and random matrix theory. We also show that these systems can be viewed as the limiting case of a properly defined sparse system. The latter result is useful when the sparse systems are easier to analyze than their dense counterparts. The list of problems we consider is by no means exhaustive. We believe that the ideas can be used in many other problems relevant for information theory.
Dynamic IDP Signature processing by fast elimination using DFA
Venue: arXiv cs.CR 2010
Year: 2010

Intrusion Detection & Prevention Systems generally aims at detecting / preventing attacks against Information systems and networks. The basic task of IDPS is to monitor network & system traffic for any malicious packets/patterns and hence to prevent any unwarranted incidents which leads the systems to insecure state. The monitoring is done by checking each packet for its validity against the signatures formulated for identified vulnerabilities. Since, signatures are the heart & soul of an Intrusion Detection and Prevention System (IDPS), we, in this paper, discuss two methodologies we adapted in our research effort to improve the current Intrusion Detection and Prevention (IDP) systems. The first methodology RUDRAA is for formulating, verifying & validating the potential signatures to be used with IDPS. The second methodology DSP-FED is aimed at processing the signatures in less time with our proposed fast elimination method using DFA. The research objectives of this project are 1) To formulate & process potential IPS signatures to be used with Intrusion prevention system. 2) To propose a DFA based approach for signature processing which, upon a pattern match, could process the signatures faster else could eliminate it efficiently if not matched
Quantum Three-Pass protocol: Key distribution using quantum superposition states
Venue: arXiv cs.CR 2010
Year: 2010

This letter proposes a novel key distribution protocol with no key exchange in advance, which is secure as the BB84 quantum key distribution protocol. Our protocol utilizes a photon in superposition state for single-bit data transmission instead of a classical electrical/optical signal. The security of this protocol relies on the fact, that the arbitrary quantum state cannot be cloned, known as the no-cloning theorem. This protocol can be implemented with current technologies.
Intelligent Detection System framework using Mobile agents
Venue: arXiv cs.NI 2010
Year: 2010

An intrusion detection system framework using mobile agents is a layered framework mechanism designed to support heterogeneous network environments to identify intruders at its best. Traditional computer misuse detection techniques can identify known attacks efficiently, but perform very poorly in other cases. Anomaly detection has the potential to detect unknown attacks; however, it is a very challenging task since its aim is to detect unknown attacks without any priori knowledge about specific intrusions. This technology is still at its early stage. The objective of this paper is that the system can detect anomalous user activity. Existing research in this area focuses either on user activity or on program operation but not on both simultaneously. In this paper, an attempt to look at both concurrently is presented. Based on an intrusion detection framework [1], a novel user anomaly detection system has been implemented and conducted several intrusion detection experiments in a simulated environment by analyzing user activity and program operation activities. The proposed framework is a layered framework, which is designed to satisfy the core purpose of IDS, and allows detecting the intrusion as quickly as possible with available data using mobile agents. This framework was mainly designed to provide security for the network using mobile agent mechanisms to add mobility features to monitor the user processes from different computational systems. The experimental results have shown that the system can detect anomalous user activity effectively.
Extended Two-Dimensional PCA for Efficient Face Representation and Recognition
Venue: arXiv cs.CV 2010
Year: 2010

In this paper a novel method called Extended Two-Dimensional PCA (E2DPCA) is proposed which is an extension to the original 2DPCA. We state that the covariance matrix of 2DPCA is equivalent to the average of the main diagonal of the covariance matrix of PCA. This implies that 2DPCA eliminates some covariance information that can be useful for recognition. E2DPCA instead of just using the main diagonal considers a radius of r diagonals around it and expands the averaging so as to include the covariance information within those diagonals. The parameter r unifies PCA and 2DPCA. r = 1 produces the covariance of 2DPCA, r = n that of PCA. Hence, by controlling r it is possible to control the trade-offs between recognition accuracy and energy compression (fewer coefficients), and between training and recognition complexity. Experiments on ORL face database show improvement in both recognition accuracy and recognition time over the original 2DPCA.
Agent Based Trust Management Model Based on Weight Value Model for Online Auctions
Venue: arXiv cs.GT 2010
Year: 2010

This paper is aimed at the stipulations which arise in the traditional online auctions as a result of various anomalies in the reputation and trust calculation mechanism. We try to improve the scalability and efficiency of the online auctions by providing efficient trust management methodology considering several factors into consideration. A comparison between the performance of the auctions system with and without the agent methodology is done with good results
Data security in mobile devices by geo locking
Venue: arXiv cs.CR 2010
Year: 2010

In this paper we present a way of hiding the data in mobile devices from being compromised. We use two level data hiding technique, where in its first level data is encrypted and stored in special records and the second level being a typical password protection scheme. The second level is for secure access of information from the device. In the first level, encryption of the data is done using the location coordinates as key. Location Coordinates are rounded up figures of longitude and latitude information. In the second phase the password entry differs from conventional schemes. Here we have used the patterns of traditional Rangoli for specifying the password and gaining access, thus minimising the chances of data leak in hostile situations. The proposed structure would be a better trade off in comparison with the previous models which use Bio Metric authentication -- a relatively costly way of authentication.
Secure Broadcasting over Fading Channels with Statistical QoS Constraints
Venue: arXiv cs.IT 2010
Year: 2010

In this paper, the fading broadcast channel with confidential messages is studied in the presence of statistical quality of service (QoS) constraints in the form of limitations on the buffer length. We employ the effective capacity formulation to measure the throughput of the confidential and common messages. We assume that the channel side information (CSI) is available at both the transmitter and the receivers. Assuming average power constraints at the transmitter side, we first define the effective secure throughput region, and prove that the throughput region is convex. Then, we obtain the optimal power control policies that achieve the boundary points of the effective secure throughput region.
The Complexity of Partition Functions on Hermitian Matrices
Venue: arXiv cs.CC 2010
Year: 2010

Partition functions of certain classes of "spin glass" models in statistical physics show strong connections to combinatorial graph invariants. Also known as homomorphism functions they allow for the representation of many such invariants, for example, the number of independent sets of a graph or the number nowhere zero k-flows. Contributing to recent developments on the complexity of partition functions we study the complexity of partition functions with complex values. These functions are usually determined by a square matrix A and it was shown by Goldberg, Grohe, Jerrum, and Thurley that for each real-valued symmetric matrix, the corresponding partition function is either polynomial time computable or #P-hard. Extending this result, we give a complete description of the complexity of partition functions definable by Hermitian matrices. These can also be classified into polynomial time computable and #P-hard ones. Although the criterion for polynomial time computability is not describable in a single line, we give a clear account of it in terms of structures associated with Abelian groups.
Message-Passing Inference on a Factor Graph for Collaborative Filtering
Venue: arXiv cs.IT 2010
Year: 2010

This paper introduces a novel message-passing (MP) framework for the collaborative filtering (CF) problem associated with recommender systems. We model the movie-rating prediction problem popularized by the Netflix Prize, using a probabilistic factor graph model and study the model by deriving generalization error bounds in terms of the training error. Based on the model, we develop a new MP algorithm, termed IMP, for learning the model. To show superiority of the IMP algorithm, we compare it with the closely related expectation-maximization (EM) based algorithm and a number of other matrix completion algorithms. Our simulation results on Netflix data show that, while the methods perform similarly with large amounts of data, the IMP algorithm is superior for small amounts of data. This improves the cold-start problem of the CF systems in practice. Another advantage of the IMP algorithm is that it can be analyzed using the technique of density evolution (DE) that was originally developed for MP decoding of error-correcting codes.
Double-Directional Information Azimuth Spectrum and Relay Network Tomography for a Decentralized Wireless Relay Network
Venue: arXiv cs.IT 2010
Year: 2010

A novel channel representation for a two-hop decentralized wireless relay network (DWRN) is proposed, where the relays operate in a completely distributive fashion. The modeling paradigm applies an analogous approach to the description method for a double-directional multipath propagation channel, and takes into account the finite system spatial resolution and the extended relay listening/transmitting time. Specifically, the double-directional information azimuth spectrum (IAS) is formulated to provide a compact representation of information flows in a DWRN. The proposed channel representation is then analyzed from a geometrically-based statistical modeling perspective. Finally, we look into the problem of relay network tomography (RNT), which solves an inverse problem to infer the internal structure of a DWRN by using the instantaneous doubledirectional IAS recorded at multiple measuring nodes exterior to the relay region.
Optimal Tradeoff Between Exposed and Hidden Nodes in Large Wireless Networks
Venue: arXiv cs.NI 2010
Year: 2010

Wireless networks equipped with the CSMA protocol are subject to collisions due to interference. For a given interference range we investigate the tradeoff between collisions (hidden nodes) and unused capacity (exposed nodes). We show that the sensing range that maximizes throughput critically depends on the activation rate of nodes. For infinite line networks, we prove the existence of a threshold: When the activation rate is below this threshold the optimal sensing range is small (to maximize spatial reuse). When the activation rate is above the threshold the optimal sensing range is just large enough to preclude all collisions. Simulations suggest that this threshold policy extends to more complex linear and non-linear topologies.
Regularized Richardson-Lucy Algorithm for Sparse Reconstruction of Poissonian Images
Venue: arXiv cs.CV 2010
Year: 2010

Restoration of digital images from their degraded measurements has always been a problem of great theoretical and practical importance in numerous applications of imaging sciences. A specific solution to the problem of image restoration is generally determined by the nature of degradation phenomenon as well as by the statistical properties of measurement noises. The present study is concerned with the case in which the images of interest are corrupted by convolutional blurs and Poisson noises. To deal with such problems, there exists a range of solution methods which are based on the principles originating from the fixed-point algorithm of Richardson and Lucy (RL). In this paper, we provide conceptual and experimental proof that such methods tend to converge to sparse solutions, which makes them applicable only to those images which can be represented by a relatively small number of non-zero samples in the spatial domain. Unfortunately, the set of such images is relatively small, which restricts the applicability of RL-type methods. On the other hand, virtually all practical images admit sparse representations in the domain of a properly designed linear transform. To take advantage of this fact, it is therefore tempting to modify the RL algorithm so as to make it recover representation coefficients, rather than the values of their associated image. Such modification is introduced in this paper. Apart from the generality of its assumptions, the proposed method is also superior to many established reconstruction approaches in terms of estimation accuracy and computational complexity. This and other conclusions of this study are validated through a series of numerical experiments.
Closed-Form Expressions for Relay Selection with Secrecy Constraints
Venue: arXiv cs.IT 2010
Year: 2010

An opportunistic relay selection based on instantaneous knowledge of channels is considered to increase security against eavesdroppers. The closed-form expressions are derived for the average secrecy rates and the outage probability when the cooperative networks use Decode-and-Forward (DF) or Amplify-and-Forward (AF) strategy. These techniques are demonstrated analytically and with simulation results.
Multi-Unit Auctions: Beyond Roberts
Venue: arXiv cs.GT 2010
Year: 2010

We exhibit incentive compatible multi-unit auctions that are not affine maximizers (i.e., are not of the VCG family) and yet approximate the social welfare to within a factor of $1+ε$. For the case of two-item two-bidder auctions we show that these auctions, termed Triage auctions, are the only scalable ones that give an approximation factor better than 2. "Scalable" means that the allocation does not depend on the units in which the valuations are measured. We deduce from this that any scalable computationally-efficient incentive-compatible auction for $m$ items and $n \ge 2$ bidders cannot approximate the social welfare to within a factor better than 2. This is in contrast to arbitrarily good approximations that can be reached under computational constraints alone, and in contrast to the fact that the optimal social welfare can be obtained under incentive constraints alone.
Seamless Data Services for Real Time Communication in a Heterogeneous Networks using Network Tracking and Management
Venue: arXiv cs.NI 2010
Year: 2010

Heterogeneous Networks is the integration of all existing networks under a single environment with an understanding between the functional operations and also includes the ability to make use of multiple broadband transport technologies and to support generalized mobility. It is a challenging feature for Heterogeneous networks to integrate several IP-based access technologies in a seamless way. The focus of this paper is on the requirements of a mobility management scheme for multimedia real-time communication services - Mobile Video Conferencing. Nowadays, the range of available wireless access network technologies includes cellular or wide-area wireless systems, such as cellular networks (GSM/GPRS/UMTS) or Wi-Max, local area Network or personal area wireless systems, comprising for example, WLAN (802.11 a/b/g) and Bluetooth. As the mobile video conferencing is considered, the more advanced mobile terminals are capable of having more than one interface active at the same time. In addition, the heterogeneity of access technologies and also the seamless flow of information will increase in the future, making the seamless integration of the access network a key challenge for mobility management in a heterogeneous network environment. Services must be provided to the user regardless of the particular access technology and also the type of service provider or the network used.